The present invention relates generally to methods and apparatus for operating a circular door assembly and, more particularly, to a method and apparatus for operating a center-open sliding door assembly.
Recently, many attempts have been made to improve apparatus for operating a center-open sliding door assembly installed at a passage of a building. FIG. 19 shows a conventional circular door assembly made up of two pairs of arcked door leaves A, each pair constituting a center-open inside door F at the inside D of a building or a center-open outside door G at the outside E, and two pairs of similarly arcked fixed panels B, each pair installed on opposite sides of the inside door F or outside door G, forming an enclosure defining a cylindrical wind blocking compartment C between the inside D and the outside E. A passenger sensor H installed in front of or at the back of the inside door F or outside door G senses the presence of a passenger or passengers to provide a signal. In response to the signal, a drive mechanism opens the corresponding door F or G. Usually, each door leaf A is slidably retreated along the corresponding curved fixed panel B.
However, these center-open sliding doors F and G open so slowly that there is a danger of blocking the passengers seeking safety in flight in the event of an emergency such as a fire or earthquake. When there is a power failure, the doors are not automatically opened so that the evacuees must open them manually, making the evacuation more difficult.